Apparatus and method for producing crumb rubber

Abstract

The apparatus and method produces fine mesh crumb rubber and provides for independently driving two parallel rolls, with one roll turning at tip speeds far above conventional cracker mills. Turning the roll at a rate (rpms) that results in “hyper” outer roll surface speeds between 1000 ft/min and 1300 ft/min., which is four and a half times the normal maximum speed of conventional mills yields several unexpected and beneficial results. The previously expected effects of operating at surface speeds about 400 ft/min are reduced or eliminated.

I claim: 
     
         1 . A method for processing material particles into smaller material particles, the method comprising:
 rotating a pair of rigid rolls disposed closely adjacent one another with a preset gap therebetween so that one of the pair of rolls turns at a tip speed between 1000 feet per minute and 1300 feet per minute; and   feeding the material particles between the pair of rolls whereby the material particles are fractured into the smaller particles.   
     
     
         2 . The method of  claim 1  wherein the preset gap between the pair of rolls exceeds the elastic limit of the material particles. 
     
     
         3 . The method of  claim 1  wherein feeding the material further includes displacing the material between the pair of rolls to compress and shear the material into particles. 
     
     
         4 . The method of  claim 1  wherein feeding the material particles between the pair of rolls compresses the material particles at a compression ratio above the elastic 1.6 limit of the material particles for a less than a 0.001 of a second. 
     
     
         5 . The method of  claim 1  wherein the other of the pair of rolls turns at a tip speed less than the one of the pair of rolls thereby creating a shear force on the material particles when feed between the pair of rolls. 
     
     
         6 . The method of  claim 1  wherein the compression ratio is above ten to one. 
     
     
         7 . A method for processing material particles into smaller material particles comprising:
 compressing the material particles at a compression ratio greater than the elastic limit of the material particles for less than 0.001 of a second, whereby the material particles fracture into the smaller material particles.   
     
     
         8 . The method of  claim 7  wherein compressing the material particles includes passing the material particles between a pair of rigid rotating rolls disposed closely adjacent one another with a preset gap therebetween. 
     
     
         9 . The method of  claim 8  wherein one of the pair of rolls turns at a tip speed between 1000 feet per minute and 1300 feet per minute 
     
     
         10 . The method of  claim 7  wherein the compression ratio is above ten to one.